Dynamically add items to an empty FormPanel using JSON

I have an empty FormPanel and I would like to add items to it dynamically depending on what the server returns using JSON. On the server I have an XML, in the XML I know exactly what types of element I got, I simply don't know their numbers, values and order - that's why I want to pick them up and render them dynamically. Example from the XML:

Thanks for your reply Rothariger. Yes, I am aware of panel.add and even tested it with some static data, works nicely. But to use it a dynamic fashion I guess I need to load and store my "items" using Ext.data.Store and then iterate through all itemsand do a panel.add for each? - Will probably work, but is this the most elegant way of doing it? FormPanel loads JSON today without any problems..

Edit: Instead of Ext.data.Store simply AJAX would do the trick, then I would have full control over it instead of having to comply with JSON (or any other format..).